Core molding machine



Feb. 22, 1955 A. H. PETERSON 2,

CORE MOLDING MACHINE Filed Feb. 25, 1951 3 Sheets-Sheet 1 INVENTOR.

fixed 1 f j si'ewso/z Feb. 22, 1955 A. H. PETE RSON 2,702,417

CORE MOLDING MACHINE Filed Feb. 23, 1951 3 Sheets-Sheet 2 a l a? 99 Feb. 22, 1955 A. H. PETERSON 2,702,417

CORE MOLDING MACHINE Filed Feb. 25, 1951 3 Sheets-Sheet 3 INVENTOR.

United States Patent CORE MOLDING MACHINE Axel H. Peterson, Rock Island, 11].

Application February 23, 1951, Serial No. 212,213

1 Claim. (Cl. 22-10) My present invention relates to molding apparatus and more particularly to apparatus for molding sand cores.

This application is a continuation-in-part of my copending application Serial No. 678,419, filed June 21, 1946, relating to a Core Molding Machine, now Patent 2,543,598 issued February 27, 1951.

Among the objects of this invention are the provision of an improved apparatus for the purpose stated; the provision of an improved apparatus for urging and holding the core sand box tightly against the core box during the core molding operation; the provision of an improved apparatus in which the sand box will be withdrawn from engagement with the core box when the pressure of the compressed air is released from the sand box; the provision of improved means for feeding compressed air into the sand box during the core-molding operation; the provision of improved means for bypassing compressed air to a side clamp causing the latter to engage a vertically split core box; the provision of improved means for relieving compressed air from the sand box whereby to minimize the amount of time necessary to complete the operation after the molding operation has been completed; and such further objects, advantages, and capabilities as will hereafter appear and as are inherent in the construction disclosed herein.

My invention further resides in the combination, construction and arrangement of parts illustrated in the accompanying drawings and, while I have shown therein what is now regarded as the preferred embodiment of this invention, together with modifications thereof, I desire the same to be understood as illustrative only and not to be interpreted in a limiting sense.

In the drawings annexed hereto and forming a part thereof:

Fig. 1 is a front elevational view of a core molding machine embodying the improvements relating to the present invention;

Fig. 2 is a plan view of the machine illustrated in Fig. 1 showing the expansible head portion per se with the sand hopper removed and With a part of the machine broken away and illustrated in section;

Fig. 3 is a fragmentary side elevational view of the upper portion of the machine looking from the left hand side of Fig. 2 to illustrate a portion of the valve operating linkage associated therewith;

Fig. 4 is a similar fragmentary side elevational view of the upper portion of the head of the core molding machine of Fig. 1 as seen from the right in Fig. 2, to further illustrate some of the valve operating mechanisms employed for operating this machine;

Fig. 5 is a vertical cross sectional view taken substantially along the line 5-5 in Fig. 2 to better illustrate the internal detail construction of the expandible head and diagrammatically illustrating the operating connections to a side clamp pressure operating unit; and

Fig. 6 is a vertical cross sectional view of one of the spring tension devices associated with the two relatively moving members of the expandible head, this section being taken on a radial plane in relation to the head.

Referring now to the arrangement of core making machine in the drawings, this machine is illustrative of a bench type core making unit having a base 80 supporting a pair of threaded uprights 81 and 82 upon which a core sand head 83 may be vertically adjusted by means of the sleeves 84 and 85 and the coacting pairs of holding nuts 86 and 87. This arrangement provides a means for fixing the relation of the head 83 with respect to the base 2,702,417 Patented Feb. 22, 1955 "ice 80 upon which core boxes such as 88 may be supported in predetermined sand receiving relation with respect to a blowplate 89 secured to a sand directing head extension 90 that is connected with the fixed head 83 through flexible diaphragm mechanism hereinafter described.

A reserve sand hopper 91 is bolted at 92 to the upper surface 93 of the head 83 and a suitable closure cap 94 removably covers the entry throat 95 comprising an upstanding annular ridge surrounding the sand admittance opening 96 in the top of the head 83. Under normal machine operation, the closure 94 will seal the opening 96 against air and sand leakage from within the head 83. As best seen in Figs. 1, 2 and 4, the head 83 is provided with a laterally positioned manifold 97 divided into a valve chamber 98 which receives compressed air through a supply pipe 99, and a distribution chamber 100 which is controlled by a valve 101 that normally closes a port 102. The distribution chamber 100 is tapped by means of a pipe line connection 103 which leads downwardly through a suitable valve 104 through a hose line 105 to a power unit 106 having a movable diaphragm 107 which is connected to actuate a clamp 108 to hold a vertically split core box such as 88 in position beneath the expandible head 83 of the core making machine. In this connection, the clamp 109 is fixed while the clamp 108 is movable with a rod 108a carried within a sleeve 110, the sleeve 110 and the supporting rod 111 being suitably held in fixed relation with respect to the vertical uprights 81 and 82 by the clamp means 112 and 113. This clamp arrangement is substantially similar to that shown and described in my copending application Serial No. 208,565, filed January 30, 1951. The valve 104 is closed when the side clamp is not being used and the clamp is normally swung out of the way for blowing horizontally split core boxes.

Referring back to Fig. 2, the distribution chamber 100 also has a port 114 formed in the wall of the head 83 for direct communication with the interior of said head. As further best illustrated in Figs. 2 and 5, the opening 96 into the head is flanked by a depending annular sleeve 115 extending from the top 93 of the head downwardly a predetermined distance below the port 114 to provide an annular pocket or chamber 116 surrounding the upper perimeter region at the top of the head and adjacent the manifold 97. As further shown in Figs. 2 and 3, the head 83 is provided with a corner extension 117 having a drilled opening 118 for receiving a vent bushing 119 therethrough to provide an air vent means for relieving the pressure from within the head 83.

Suitable mechanism is employed for quickly operating the valve 101 for admission of air from the supply chamber 98 into the distribution chamber 100. Such valve operating means includes a push rod 120 operated through a supporting gland or sleeve 121 and connected with the valve 101 at 122 with the exposed end of the push rod 120 connected by a pair of links 123 to an operating arm 124 that is connected to one end of a cross shaft 125. The links 123 have elongated holes 1231: to enable the arm 124 to move before movement is transmitted to the push rod 120 of valve 101. Arm 124 terminates in a handle or hand grip 126, and operation of this handle toward and away from the head of the machine in Fig. 1 rocks the shaft 125 within the bearing lugs 127 and 128, to also manipulate the arm 129 which is pivotally connected at 130 to one end of a bar 131. As best seen in Figs. 2 and 3, the bar 131 carries a slot 132 through which a pin 133 connects with the end 134 of a bell crank 135. Bell crank 135 is pivotally supported at 136 on the head 83 and the other end 137 of the bell crank is provided with adjustable means 138 to support a rubber ended valve head 139 in aligned relation to the vent sleeve 119.

As shown in Fig. 3, a tension spring 140 is connected between a stud 141 on the head 83 and through an opening 142 in the bar 131 to normally maintain bar 131 to the right, and this tension of the bar is transmitted through the arm 129 and across shaft 125 to the arm 124 to maintain the valve 101 in closed position against the division wall 143 of the manifold 97.

As seen in Figs. 2 and 3, a second tension spring 144 is connected to the opposite outwardly extending ends of the pin 133 and is looped through an opening 145 in the bar 131 to normally hold pin 133 against the spring side of the slot 132, which also establishes a predetermined clearance between the rubber valve 139 and the bushing 119.

By moving the handle 126 of Fig. 1 toward the machine, arm 124 may be moved against the head 146 of an adjustable stop bolt 147 carried in a lug 148 adjacent the head 83. The first portion of the movement of the arm 124 rotates shaft 125 to operate the link mechanism to bring the rubber valve head 139 into closing contact with the vent bushing 119, and the continued movement of the handle 124 toward the bolt head 146 will open the valve 101 to admit air under pressure through the supply line 99 and chamber 98 into the d1stribution chamber 100, which builds up pressure in the head 83 and forces sand out of the opening 149 in the blow plate 89 and in the direction of the core box 88. Release of the handle 126 closes the compressed air supply valve 101 and thereafter opens the vent bushing 119 as the rubber head 139 is moved away therefrom through the lost motion arrangement of the linkage adequately provided for by means of the pin 133 and slot 132.

Referring now more particularly to F1g. 5, a flexible, laterally extending diaphragm 150 is secured to the bottom edge 151 of the head 83 by means of a peripheral ring 152 and a plurality of bolts 153. The adjacent end of the sand head extension 90 is also secured to the outer peripheral portion of the flexible diaphragm 150 by means of an outer securing ring 154, the described parts being connected by suitable bolts 155 positioned about the periphery of the ring 154.

With this particular flexible arrangement, the head 83 and the head extension 90 may be moved relatively to each other and since the head 83 is fixed in relation to the core machine making parts, head 90 will move downwardly under the force of internal pressure to span the gap 156 shown in Fig. 1 for engaging the core box 88.

It should further be noted as illustrated in Fig. 5, that the head 83 and extension 90 are normally filled with considerable core sand so that the incoming compressed air into the distribution chamber 100 will encounter considerable resistance within the head 83 and obviously, a considerable portion of this air will first pass out of the pipe line 103 downwardly to the power unit 106 to operate the side clamp arrangement indicated in Fig. 1. This clamp action, therefore, precedes the movement of the head 90 downwardly toward the core box 88.

It has further been found that the provision of the annular pocket 116 at the head of the cylinder is normally clear of sand and that the outrush of the compressed air through port 114 actually picks up very little sand that might be discharged out of the vent bushing 119 on the exhaust cycle. As shown in Fig. 5, the exhaust vent 119 is located high in the head 83 and at the top of the air pocket chamber 116.

It has been found desirable to provide limiting means for controlling the relative movement of the head extension 90 with respect to the core sand head 83, and it has also been found necessary to introduce means to return the head extension to a normal position after the blowing cycle.

Such a means is best illustrated in Fig. 6 as a spring unit 157, four of which are used in combination with the flexible joint and two of which are illustrated in Fig. 1. Each of these spring units, as seen in Fig. 6, includes a stud 158 threaded into an opening 159 in the ring 154 and locked in place by means of a nut 155 to fix the extended portion of the stud in a given relation with respect to the movable head extension 90. This stud 158 passes through an opening 159' in the lug 160 forming a part of the head 83 and an expansion spring 161 is interposed between the top of the lug 160 and a washer 162 secured in place by an adjustable nut 163 threaded upon the end of the stud 158. In addition, stud 158 is shouldered as at 164 for engagement with the upper surface 165 of the lug 160.

Each of the spring units functions through the instrumentality of the spring 161 to hold the nut 155 on the stud in abutting contact with the surface 166 at the bottom of the lug 160. In order that the head extension may move downwardly with respect to the head 83, the expansive force of the spring 161 must first be overcome, at which time the diaphragm will flex, permitting downward movement of the head end 90. By adjusting the nut 163, a variable tension may be introduced into the spring unit through the compression or expansion of spring 161. If the tension of springs 161 is too great, the'sand will move out before the head moves. down. This tension is therefore critical. This spring ad ustment arrangement has been found advantageous in allowing for different sand conditions and to adjust the relative tension of the expandible head sections to return section 90 after the blowing cycle, but not to impair movement between sections as would cause sand to discharge from the head prior to contact with a core box.

Shoulder 164 on the stud 158 provides a means for limiting the total expansion of the overall length of the combined heads 83 and 90, and this limit may be adjusted through the threaded end 159 of the bolt and the nut 155.

However, in the construction illustrated in Fig. 1, the clamp mechanism is supported independently of the movable head portion of the machine, and in this construction it is preferable to have the lateral clamp action take place prior to the vertical clamp action of the head against the box.

Since various modifications may be possible in carrying out the fundamental concept of this invention, applicant does not intend to be limited excepting as to the breadth and scope of the appended claim directed to the invention.

What I claim is:

A sand blowing structure for a core making machine comprising at least one pair of separable air confining sand containers, a flexible sealing means connecting said containers for relative movement therebetween, and adjustable tensioning means interposed between said containers to coact with said flexible sealing means and arranged to return said containers to a non-operative position, and said adjustable tensioning means each comprising a stud having one end carried by one container, an apertured lug on said other container receiving said stud therethrough, a spring on the other end of said stud and abutting said lug, tension adjusting means on said stud engaging said spring, said spring acting to keep said containers together, and said lug comprising a stop to contact a portion of the other container to limit the motion of the containers toward each other.

References Cited in the file of this patent UNITED STATES PATENTS 981,262 Heim Jan. 10, 1911 1,563,156 Burman Nov. 24, 1925 2,543,598 Peterson Feb. 27, 1951 FOREIGN PATENTS 130,665 Switzerland Dec. 31, 1928 59,355 Sweden Apr. 30, 1923 

